1. Field of the Invention
This invention relates to an image pickup apparatus for picking up an object image and an image pickup system including the apparatus.
2. Related Background Art
U.S. Pat. No. 4,410,804 discloses a conventional image pickup apparatus in which one microlens is provided for a plurality of photoelectric conversion elements to expose the respective photoelectric conversion elements to projected images obtained from different points of view and thereby detect the distance based on a phase difference detecting method.
FIG. 1 is a plan view showing a solid-state image pickup element disclosed in U.S. Pat. No. 4,410,804 or the like. FIG. 1 shows that pixels 205 each having a plurality of photodiodes 201 to 204 are formed on a matrix. A common microlens (not shown) is placed above the pixels 205, and exposure signals of images obtained from the different points of view are accumulated in the respective photodiodes 201 to 204.
Exposure signals of images obtained from a same point of view are accumulated in the photodiodes 201 to 204 denoted by the same reference numerals in each of the pixels 205. Exposure signals of images obtained from the different points of view are accumulated in the photodiodes 201 to 204 in each of the pixels 205. An amount of a shift in focus can be found by correlating the exposure signals of images obtained from the different points of view.
An object of the present invention is to provide an image pickup apparatus capable of suitably adjusting a focus. To achieve the above object, according to one aspect of the present invention, there is provided an image pickup apparatus comprising: first and second photoelectric conversion units each including a plurality of photoelectric conversion elements; an image forming unit that forms images viewed from different points on the plurality of photoelectric conversion elements included in each of the first and second photoelectric conversion units; a first holding unit for holding signals from the first photoelectric conversion unit, the first holding unit having at least the same number of capacitors as the number of the plurality of photoelectric conversion elements included in the first photoelectric conversion unit; a second holding unit for holding signals from the second photoelectric conversion unit, the second holding unit having at least the same number of capacitors as the number of the plurality of photoelectric conversion elements included in the second photoelectric conversion unit; and a first common output line to which signals are read out from the plurality of capacitors included in each of the first and second holding units.
Also, according to another aspect of the present invention, there is provided an image pickup apparatus comprising: first and second photoelectric conversion units each including a plurality of photoelectric conversion elements; microlenses provided respectively in the first and second photoelectric electric conversion units, for focusing light onto the plurality of photoelectric conversion elements included in each of the first and second photoelectric conversion units; a first holding unit for holding signals from the first photoelectric conversion unit, the first holding unit having at least the same number of capacitors as the number of the plurality of photoelectric conversion elements included in the first photoelectric conversion unit; a second holding unit for holding signals from the second photoelectric conversion unit, the second holding unit having at least the same number of capacitors as the number of the plurality of photoelectric conversion elements included in the second photoelectric conversion unit; and a first common output line to which signals are read out from the plurality of capacitors included in the respective ones of the first and second holding units.
According to still another aspect of the present invention, there is provided an image pickup apparatus comprising: an image pickup area having a plurality of photoelectric conversion elements; and a plurality of microlenses that focus light onto the plurality of photoelectric conversion elements; wherein one microlens is provided for every one photoelectric conversion element in a first image pickup region in the image pickup area, and one microlens is provided for every a plurality of photoelectric conversion elements in a second image pickup region in the image pickup area.
Other objects and features of the present invention will become apparent from the following description of the embodiments taken in conjunction with the accompanying drawings.